DR.T.V.RAO MD 1

Dr.T.V.Rao MD

HELICOBACTER PYLORIUPDATE

HISTORY OF H. PYLORI• 1890’s: Spirochetes in animal stomachs

• 1900’s: Spirochetes in human stomachs

• 1954: No bacteria in gastric biopsies of 1000 patients

• 1975: Gram negative bacteria in 80% of GU’s (Pseudomonas)

• 1983: Warren and Marshall characterize H. pylori

• 2005 Nobel prize in 2005

DR.T.V.RAO MD 3

HELICOBACTER PYLORI

Background

Human stomach long considered inhospitable forbacteria

Spiral shaped organisms occasionally visualized ingastric mucous layer, but no evidence of diseaseassociation

Organism classified first as Campylobacter pylori

Now Helicobacter pylori

Other species of Helicobacter isolated fromstomach, intestine of other animals

Marshall and Warren culture organism from humangastric mucosa and show association with gastricinflammation

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HELICOBACTER( WARREN AND MARSHAL )

• Campylobacter like organisms

• Spiral shaped colonizes Gastric mucosa

• Etiological agent in Gastritis and peptic ulcer

• Most important bacteria.

Helicobacter pylori

Colonizes 50 % of the Individuals

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WARREN AND MARSHAL WINS NOBEL PRIZE

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GENERAL CHARACTERISTICS OF HELICOBACTER

• Helicobacter pylori is major human pathogen associated with gastric antral epithelium in patients with active chronic gastritis

• Stomach of many animal species also colonized

• Urease (gastric strains only), mucinase, and catalase positive highly motile microorganisms

• Other Helicobacters: H. cinnaedi and H. fenneliae

• Colonize human intestinal tract

• Isolated from homosexual men with proctitis, proctocolitis, enteritis, and bacteremia and are often transmitted through sexual practices

DR.T.V.RAO MD 7

A silver stain of H. pylori on gastric mucus-secreting epithelial cells (x1000).

From Dr. Marshall's stomach biopsy taken 8 days after he drank a culture of H. pylori

(1985).

HELICOBACTER PYLORI

• Gram –ve spiral shaped , motile with unipolar tuft of lopotrichus flagella

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H. PYLORI BACTERIA

• Gram negative

• Spiral rod

• Unipolar flagella

• Microaerophilic

• Urease positive*

*Most important

character

*Scanning microscopic view of H. pylori

MORPHOLOGY & PHYSIOLOGY OF HELICOBACTER

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• Gram-negative; Helical (spiral or curved) (0.5-1.0 um X 2.5-5.0 um); Blunted/rounded ends in gastric biopsy specimens; Cells become rod-like and coccoid on prolonged culture

• Produce urease, mucinase, and catalase

• H. pylori tuft (lophotrichous) of 4-6 sheathed flagella (30um X 2.5nm) attached at one pole

• Single polar flagellum on H. fennellae & H. cinaedi

• Smooth cell wall with unusual fatty acids

• Transmissible• Oral-oral and oral-fecal

• Infects the human stomach

• Produces inflammatory response

• This brings up the point of the importance of “hand washing”

H. PYLORI INFECTION TRANSMISSION

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DYNAMICS OF H.PYLORI INFECTION

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CULTURING AND BIOCHEMICAL CHARACTERS

• Grows on chocolate agar, Campylobacter media

• Grows under Microaerophilic conditions

• With presence of 5 – 20% co2

• Oxidase +

• Catalase –

• Urease strongly +++

• H2S

H. PYLORI PATHOGENESISBACTERIAL VIRULENCE FACTORS

(CAG- PAI)( 37000 B-P – 29 GENES)

• Type IV secretions apparatus(1) (translocate cag A)

• Possible insertion by needle like organelle coated with a sheath (Cag 7 protein) [Rohde et al]

• Phosphorylated + binds to SHP-2 tyrosine Phosphates

Cytokine Production Growth Factor

IL- 8+ chemokines Like cellular response

(1) Odenbreit S, et al. Science 2000;287:1497-1500

H. PYLORI PATHOGENESISBACTERIAL VIRULENCE FACTORS

Ingestion Evasion + Entrance of Mucus

1 Layer (Motility + Urea I)

2 Binding

3 Insertion

4 Intra cellular pathway

HELICOBACTER PYLORI AND PEPTIC ULCER DISEASEHISTOPATHOLOGY WITH SPECIAL STAINS .

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H. PYLORI PATHOGENESISTHE ROLE OF CYTOKINES

I. Alter secretion of mucus

II. TNF–α IL–Iß, INF- 1Y

• ↑ Gastrin release Stimulate parietal cells

↑ Acid secretion

III. TNF–α ↓ D cells number

↓ Somatostatin

↑ Acid secretion

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PATHOLOGY AND PATHOGENESIS• H.pylori colonizes gastric mucosa• Spread by oral – oral contact• Feco oral spread prominent• Poverty and overcrowding predisposes• Poor Hygiene• Causes mild to acute gastritis • Gastric antrum - causes gastric metaplasia• Any part of the stomach can be involved• Colonizes overlying mucosa but donot invade mucosa

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MAJOR LOCATION OFH.PYLORI INFECTIONS

Colonize mucosal lining of stomach & duodenum in man & animals • Adherent to gastric surface epithelium or pit epithelial

cells deep within the mucosal crypts adjacent to gastric mucosal cells

• Mucosa protects the stomach wall from its own gastric milleu of digestive enzymes and hydrochloric acid

• Mucosa also protects Helicobacter from immune response

Most gastric adenocarcinomas and lymphomas are concurrent with or preceded by an infection with H. pylori

Pathogenesis of Helicobacter Infections

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H.PYLORI INFECTING MUCOSAL LAYER

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PATHOGENESIS OF H.PYLORI.

Multiple polar, sheathed flagella• Corkscrew motility enables penetration into viscous

environment (mucus)

Adhesins: Hemagglutinins; Sialic acid binding adhesin; Lewis blood group adhesin

Mucinase: Degrades gastric mucus; Localized tissue damage

Urease converts urea (abundant in saliva and gastric juices) into bicarbonate (to CO2) and ammonia• Neutralize the local acid environment• Localized tissue damage

Acid-inhibitory protein

Virulence Factors of Helicobacter

H. Pylori Specific T Cell and B Cell Responses

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MECHANISM OF H.PYLORI INFECTION

Urease C=O(NH2)2 + H+ + 2H2O HCO3

- + 2 (NH4+)

Urea Bicarbonate Ammonium ions

And then… HCO3-

CO2 + OH-

Urea Hydrolysis

Tissue damage: Vacuolating cytotoxin: Epithelial cell damage Invasin(s)(??): Poorly defined (e.g., hemolysins;

phospholipases; alcohol dehydrogenase)

Protection from phagocytosis & intracellular killing: Superoxide dismutase Catalase

Virulence Factors of Helicobacter )

H. Pylori Pathogenesis and Application of Cutting Edge Technologies

Molecular biology

Genetics Imaging Cell culture models

INDICATIONS FOR NONINVASIVE TESTING FOR H. PYLORI *

• Strongly Recommended• Dyspepsia

• History of/active peptic ulcer disease

• Gastric MALT lymphoma

• Following gastric cancer resection

• Following peptic ulcer surgery

• First-degree relative with gastric cancer

• Long-term Non-steroidal anti-inflamatory drugs (NSAID) therapy

* In the absence of alarm signs for gastric cancer or ulcer disease1. Malfertheiner P, et al. Aliment Pharmacol Ther. 2002;16:167. 2. Talley NJ et al. Aliment Pharmacol Ther.1999;12:1135.

TYPES OF H. PYLORI TESTS

• Endoscopy

• Rapid urease tests

• Histology

• Culture

• Serologic (antibody)

• Stool antigen tests

• 13C Urea blood test• Urea breath tests

•14C-urea

•13C-urea

Malfertheiner P, et al. Aliment Pharmacol Ther. 2002;16:167.

• Detects active infection

• Sensitive and specific

• Non-radioactive

• No special handling requirements

• Easy to collect and handle sample

• Not indicated in pediatric population

13C UREA BREATH TEST

1. Graham DY et al. Am J Gastroenterol. 2001;96:1741. 2. Leodolter A et al. Am J Gastroenterol. 1999;94:2100.

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LABORATORY DIAGNOSIS• Diagnosed by Invasive and Non Invasive tests• Invasive, Endoscopic Biopsy of Gastric mucosa• Microscopy – Biopsy• Culture • Staining by special stains• Gram staining• Culture more sensitive 3 – 7 days• Biopsy testing for urease detection in urea medium

Laboratory IdentificationRecovered from or detected in endoscopic antral

gastric biopsy material; Multiple biopsies are takenMany different transport media Culture media containing whole or lysed bloodMicroaerophilicGrow well at 37oC, but not at 25 nor 42oCLike Campylobacter, does not use

carbohydrates, neither fermentatively nor oxidatively

DIAGNOSIS BY NON INVASIVE METHODS

• Serology ELISA

• Urea breath test patient swallows urea solution

In this test patient drinks urea solutions labeled with an isotope carbon

If H.pylori is present in the urea is converted to ammonia and co2 in the breath measured.

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SUGGESTED GUIDELINES FORTREATMENT OF PATIENTS WITH GI OR ULCER

DISEASE

History & Physical Exam

Peptic ulcerdisease

Undifferentiateddyspepsia

Symptomsof GERD

Use of NSAIDsor aspirin

Positive

Eradicationtherapy

Confirmation of cure

Test for H. pylori

Malfertheiner P, et al. Aliment Pharmacol Ther. 2002;16:167.

SUGGESTED GUIDELINES FORTREATMENT OF PATIENTS WITH GI OR ULCER

DISEASE

History & Physical Exam

Peptic ulcerdisease

Undifferentiateddyspepsia

Symptomsof GERD

Use of NSAIDsor aspirin

Positive

Eradicationtherapy

Confirmation of cure

Negative

Treat for PUD,Initiate PPI therapy,

or discontinue NSAIDs

Test for H. pylori

Malfertheiner P, et al. Aliment Pharmacol Ther. 2002;16:167.

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TREATMENT

• Use of antibiotics, bismuth salts• Ingestion of Bismuth subsalicylate• Antibiotics Tetracycline's and metronidazole for two weeks• Use of Omeprazole• Clarithromycin• Do not treat for Asymptomatic colonization• Drug resistance is a growing problem

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• Antibiotic treatment does not always completely inhibit or kill H. pylori with potential for antibiotic resistance. Resistance to antibiotics is the single most important factor for declining H. pylori eradication rates.

• In Japan, resistance to antibiotic drugs has increased 400% while in Taiwan, it is 500%. This means that those who are infected while in these countries may find the bacterium rather resistant to their antibiotic treatments.

EMERGING DRUG RESISTANCE IN H.PYLORI

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EPIDEMIOLOGY OF HELICOBACTER INFECTIONS

• Developed Countries:

• United States: 30% of total population infected

• Of those, ~1% per year develop duodenal ulcer

• ~1/3 eventually have peptic ulcer disease(PUD)

• 70% gastric ulcer cases colonized with H. pylori

• Low socioeconomic status predicts H. pylori infection

• Developing Countries:

• Hyperendemic

• About 10% acquisition rate per year for children between 2 and 8 years of age

• Most adults infected but no disease

• Protective immunity from multiple childhood infections

H.PYLORI CONTINUES TO BE AN IMPORTANT PATHOGEN

• H. pylori is a transmissible, infectious disease with potentially serious outcomes

• H. pylori infection may be asymptomatic or cause dyspepsia

• Eradication therapy can cure H. pylori infection and prevent morbidity and downstream events such as PUD and gastric cancer

• Patients with symptoms of upper-GI disease, and who use aspirin or NSAIDs should be tested for H. pylori infection

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• Programme Created by Dr.T.V.Rao MD for Medical and Health Care Workers in

the Developing World• Email

• doctortvrao@gmail.com